Rectangular Waveguide Narrow Side Gap Line Array Antenna

Marine CW radar transceiver antenna should be compact and have narrow beam width, light weight and high isolation. Using a single rectangular waveguide with slots in the narrow side, an array antenna with narrow beam width and low side-lobe level could be achieved. Furthermore, if this antenna structure is improved, a compact, low-side-lobe and high isolated dual-antenna (transmitting antenna and receiving antenna) could be achieved.This paper mainly studies the Marine CW radar transceiver antenna. Based on narrow rectangular waveguide slot antenna linear array, a low-side-lobe narrow rectangular waveguide slot antenna is studied by two feeding methods. Then two center-feeded antennas combine into one transceiver antenna. Dual antenna structures are researched with a large number of innovative and exploratory actions. The research work as follows:First, based on the transmission line equivalent circuit of rectangular waveguide with narrow side slots, the angle distribution of slots in rectangular waveguide narrow side has been deduced. Then end-feeding antenna of rectangular waveguide narrow slot array is researched by Chebyshev weighted and Taylor weighted respectively. A low side-lobe narrow rectangular waveguide slot linear array antenna is designed by CST and MATLAB. After comparing the Chebyshev-weighted antenna pattern to the Taylor-weighted antenna pattern, it is known that Taylor weighting is better than the weighted Chebyshev.Secondly, the transition of coaxial to waveguide is studied. The center-feeding low side-lobe slots antenna of narrow rectangular waveguide is designed with Taylor-weighted distribution. After several structures of dual antenna are explored and analyzed, a high isolation and compact dual antenna is completed. The antenna center frequency is 9.41GHz, bandwidth is 60MHz, isolation is more than 60dB, side-lobe level is less than -20dB, gain is more than 20dB and VSWR is less than 2.Finally, gain, pattern, isolation and VSWR of the antenna are measured; then comparison between the measured data and the simulated data is carried, and the differences between the simulation data and the measured data are analyzed.